In order to facilitate voice communication, a cellular telephone generally includes an integrated microphone and an integrated speaker, each optimally positioned at an exterior surface of the cellular telephone so that a user can hold the cellular telephone with the speaker near the user's ear and the microphone within range of the user's mouth. Audio processing circuitry in the cellular telephone delivers to the speaker outbound audio signals representative of audible communications, for presentation of the audible communications to the user. Likewise, the audio processing circuitry receives from the microphone and processes audio signals representative of audible communications received by the microphone.
For the user's convenience or safety, a typical cellular telephone also includes a mechanism to connect with an external microphone/speaker combination through a wireless or wired link. For instance, the cellular telephone may include a short-range wireless interface, such as a BLUETOOTH or WI-FI interface (or other frequency hopping spread spectrum connection mechanism) or an infrared interface, that is arranged to pair with a correspondingly equipped headset having both microphone and speaker components, or the cellular telephone may include a jack for receiving a plug that provides a corded connection with a headset having both microphone and speaker components.
When an external headset is paired or otherwise connected with the cellular telephone, the audio processing circuitry in the cellular telephone causes audible communications to be routed between the cellular telephone and the external headset rather than between the cellular telephone and the integrated microphone and speaker. A user of the cellular telephone may thus conveniently engage in a voice call without the need to hold the cellular telephone with the integrated speaker near the user's ear or the integrated microphone near the user's mouth.